Versatile process for the preparation of acylphosphines

ABSTRACT

A versatile, highly efficient process for the preparation of acylphosphines such as mono- and bisacylphosphines via reaction of phosphines (PH3 and higher homologues) or silylated phosphines with acylhalides in the presence of at least one lewis acid. Further a novel acyl phosphines obtainable by the process.

The present invention relates to a versatile, highly efficient processfor the preparation of acylphosphines such as mono- andbisacylphosphines via reaction of phosphines (PH₃ and higher homologues)or silylated phosphines with acylhalides in the presence of at least onelewis acid. The invention further relates to novel acyl phosphinesobtainable by said process.

Photoinitiators, in particular mono- and bisacylphosphine oxides, inparticular those bearing further functionalized substituents haveattracted significant commercial attention since photoinitiators whichare tunable with respect to the wavelength at which photoinducedcleavage occurs or which are linkable to other additives, such assensitizers, stabilizers or surface active agents are highly desirable.

Industrial applications of mono- and bisacylphosphine oxides include themanufacture of pigmented and clear coatings, adhesives, inks,photo-resists, printing plates, and dental restoring materials.

However, the synthesis of mono- and bisacylphosphines as standardprecursor materials for the corresponding oxides requires the use ofhighly reactive phosphanes and is thus difficult to manage at industrialscale. Specifically, for known synthesis of bisacylphosphines, hazardouschemicals such as primary phosphanes, RPH₂, are used.

Moreover, this approach does not allow to attach functional groups otherthan simple alkyl or aryl groups as group R to the phosphorus center.

At present, the only industrially viable route to substitutedbisacylphosphines requires as a first step the synthesis ofbisacylphosphines, HP(COR)₂ as intermediates which are obtained byacylation of a metal dihydrogenphosphide M(PH₂). M(PH₂) can be obtainedfrom elemental phosphorus by reaction with a strongly reducing metalsuch as lithium, sodium, or potassium, and catalytic amounts ofnaphthalene, followed by protonation of the resulting trisodiumphosphide (Na₃P) with tert-butanol (see WO2006/056541A).

The resulting bisacylphosphines, HP(COR)₂ may then be further reactedwith functionalized halo compounds (WO2006/056541A) or even withacrylates or other electrophiles as disclosed in WO2014/053455A toobtain functionalized bisacylphosphines RP(COR)₂ which are thenconverted to the corresponding bisacylphosphine oxides O═PR(COR)₂ bysimple oxidation. Similar reaction sequences are disclosed inWO2010/121387A and WO2011/003772A.

Alternatively, EP 1 135 399 A discloses a process for the preparation ofmono- and bisacylphosphines and their respective oxides and sulfides.The process comprises the steps of reacting substitutedmonohalophosphanes or dihalophosphanes with an alkali metal or acombination of magnesium and lithium, where appropriate in the presenceof a catalyst, further reacting the resulting metallated phosphanes withcarboxylic acid halides and finally oxidizing the resulting mono- orbisacylphosphanes with sulfur or oxygen transferring oxidants.

It is further known from WO05/014605A to prepare substitutedbisacylphosphines via a process comprising the steps of first reactingmonohalophosphanes or dihalophosphanes with an alkali metal in a solventin the presence of a proton source and then reacting the phosphanesobtained thereby with carboxylic acid halides.

WO2006/074983A discloses a process for the preparation ofbisacylphosphines by first catalytically reducing monochloro- ordichlorophosphines with hydrogen at a temperature of from 20 to 200° C.under pressure in the presence of a tertiary aliphatic amine or anaromatic amine in an aprotic solvent to obtain the correspondinghalogen-free phosphanes and subsequently reacting said phosphanes withcarboxylic acid halides to obtain mono- or bisacylphosphines.

However, for the variation of the non-acyl substituent(s) at thephosphorous atom the aforementioned processes, even though some of themcan be performed as a one-pot procedure either require

-   -   the initial employment of an organic mono- or dihalophosphane        already bearing such substituent(s) in a first reduction or        metallation step which significantly diminishes the variability        of possible substitution patterns, or    -   if e.g. alkali metal phosphides such as Na₃P or NaPH₂ are        employed, handling of elemental phosphorus and a strongly        reducing alkali metals        which renders such processes commercially less attractive.

Attempts to prepare mono- or bisacylphosphanes (H₂P(COR) and HP(COR)₂directly from readlily available phosphine (PH₃) have failed so far.

Albers et al. attempted the acylation of PH₃ with acetyl chloride in thepresence of AlCl₃, but were not able to isolate any products (H. Albers,W. Künzel, W. Schuler, Chem. Ber. 1952, 85, 239-249). Issleib likewisereports failure to prepare acylphosphanes from PH₃ and variousacylhalides (K. Issleib, E. Priebe, Chemische Berichte 1959, 92, 3183).This was later confirmed by Becker et al. In: G. Becker, Zeitschrift fürAnorganische und Allgemeine Chemie 1981, 480, 21.

Evans et al. prepared benzoylphosphine by bubbling PH₃ through neatbenzoylchloride, albeit in very low yield (P. N. Evans, J. Tilt, Am.Chem. J. 1910, 44, 362). Platzek et al. prepared tris(acyl)phosphines bytreating solutions of acid chlorides in pyridine with PH₃ (R. Tyka, E.Plazek, Bulletin de l'Academie Polonaise des Sciences, Serie desSciences Chimiques 1961, 9, 577-584). Due to the numerous possible sidereactions, the products obtained are of low purity and thus not suitableto be industrially employed.

The acylation of silylphosphines has been reported (G. Becker,Zeitschrift für Anorganische und Allgemeine Chemie 1981, 480, 38; G.Becker, H. P. Beck, Zeitschrift für Anorganische und Allgemeine Chemie1977, 430, 77; G. Becker, M. Rössler, G. Uhl, Zeitschrift fürAnorganische und Allgemeine Chemie 1982, 495, 73; G. Becker, W. Becker,M. Schmidt, W. Schwarz, M. Westerhausen, Zeitschrift für Anorganischeund Allgemeine Chemie 1991, 605, 7; G. Märkl, H. Sejpka, TetrahedronLetters 1986, 27, 1771; A. S. Ionkin, L. F. Chertanova, B. A. Arbuzov,Phosphorus, Sulfur and Silicon and the Related Elements 1991, 55,133-136 wherein the compound diphenylborylpivaloylphosphide isexplicitly mentioned; H. Nöth, S. Staude, M. Thomann, J. Kroner, R. T.Paine, Chemische Berichte 1994, 127, 1923).

The acylation of polyphosphides or polyphosphines has not been reportedto date.

As a consequence, and in view of the restrictions described above thereis still a need for a highly efficient and versatile process to prepareacylphosphines, in particular mono- or bisacylphosphines.

A process was now found for the preparation of compounds of formula (I):[LAF]_(s)[P_(x)(R^(H))_(m)(R¹)_(n)(COR²)_(p)]_(q)  (I)wherein

-   s is either 0 or, provided that x is 1, m and n are 0 and p is 2, s    is 1-   q if s is 0, is 1 and    -   if s is 1, is an integer of 1 to 5, preferably 1, 2 or 3, more        preferably 1 or 3-   x is an integer of 1 to 15 or 20-   m, n and p are selected such that:    -   m is zero or an integer of 1 or more    -   n is zero or an integer of 1 or more    -   P is an integer of 1 or more    -   and one of the following conditions is met:

If x is an integer of 1 to 9  (m+n+p) is (x+2) where s is 0 (m+n+p) is(x+1) where s is 1 x is an integer of 3 to 10  (m+n+p) is x x is aninteger of 4 to 12  (m+n+p) is (x−2) x is an integer of 5 to 10 or 13(m+n+p) is (x−4) x is an integer of 7 to 14 (n+m+p) is (x−6) x is 10, 11or 15 (m+n+p) is (x−8) x = is 12 or 20 (m+n+p) is (x−10)

-   LAF represents a q-valent Lewis Acid Fragment (LAF) as defined    hereinafter,-   R^(H) are independently of each other either    -   hydrogen,    -   or a residue of formula Si(R³)₃, wherein the substituents R³ are        independently of each other selected from the group consisting        of C₁-C₁₈-alkyl and C₆-C₁₄-aryl-   R¹ and R² are independently of each other aryl or heterocyclyl,    alkyl or alkenyl    -   whereby the aforementioned alkyl and alkenyl substituents R¹        and/or R² are        -   either not, once, twice or more than twice interrupted by            non-successive functional groups selected from the group            consisting of:        -   —O—, —NR⁴—, —CO—, —OCO—, —O(CO)O—, NR⁴(CO)—, —NR⁴(CO)O—,            O(CO)NR⁴—, —NR⁴(CO)NR⁴—,        -   and        -   either not, additionally or alternatively either once, twice            or more than twice interrupted by bivalent residues selected            from the group consisting of heterocyclo-diyl, and aryldiyl,        -   and        -   either not, additionally or alternatively either once, twice            or more than twice substituted by substituents selected from            the group consisting of:        -   oxo, halogen, cyano, C₆-C₁₄-aryl; heterocyclyl,            C₁-C₈-alkoxy, C₁-C₈-alkylthio, —SO₂N(R⁴)₂, —NR⁴SO₂R⁵,            —N(R⁴)₂—, —CO₂N(R⁴)₂, —COR⁴—, —OCOR⁵, —O(CO)OR⁵, NR⁴(CO)R⁴,            —NR⁴(CO)OR⁴, O(CO)N(R⁴)₂, —NR⁴(CO)N(R⁴)₂,            whereby in all formulae where used-   R⁴ is independently selected from the group consisting of hydrogen,    C₁-C₈-alkyl, C₆-C₁₄-aryl, and heterocyclyl or N(R⁴)₂ as a whole is a    N-containing heterocycle,-   R⁵ is independently selected from the group consisting of    C₁-C₈-alkyl, C₆-C₁₄-aryl, and heterocyclyl or N(R⁵)₂ as a whole is a    N-containing heterocycle    the process comprising at least the step of reacting compounds of    formula (II)    P_(x)(R^(H))_((m+p))(R¹)_(n)  (II)    wherein R^(H), R¹, x, and n and the sum of (m+n+p) is as defined    above for the sum of (m+n+p) for compounds of formula (I) with s    being 0 where x=1    and the sum of (m+p) is an integer of 1 or more that fits the    equation given for the sum of (m+n+p) for compounds of formula (I)    with s being 0 where x is 1    with compounds (carboxylic acid halides) of formula (III),    R²COHal  (III)    wherein R² is as defined above for compounds of formula (I) and-   Hal represents fluoro, chloro, bromo or iodo, preferably chloro or    bromo and even more preferably chloro    whereby the reaction is carried out in the presence of at least one    lewis acid.

The scope of the invention encompasses all combinations of substituentdefinitions, parameters and illustrations set forth above and below,either in general or within areas of preference or preferredembodiments, with one another, i.e., also any combinations between theparticular areas and areas of preference.

Whenever used herein the terms “including”, “e.g.”, “such as” and “like”are meant in the sense of “including but without being limited to” or“for example without limitation”, respectively.

As used herein, and unless specifically stated otherwise, aryl denotescarbocyclic aromatic substituents, whereby said carbocyclic, aromaticsubstituents are unsubstituted or substituted by up to five identical ordifferent substituents per cycle. For example and with preference, thesubstituents are selected from the group consisting of fluorine,bromine, chlorine, iodine, nitro, cyano, C₁-C₈-alkyl, C₁-C₈-haloalkyl,C₁-C₈-alkoxy, C₁-C₈-haloalkoxy, protected hydroxyl, protected formyl,C₆-C₁₄-aryl such as phenyl and naphthyl, di(C₁-C₈-alkyl)amino,(C₁-C₈-alkyl)amino, CO(C₁-C₈-alkyl), OCO(C₁-C₈-alkyl),NHCO(C₁-C₈-alkyl), N(C₁-C₈-alkyl)CO(C₁-C₈-alkyl), CO(C₆-C₁₄-aryl),OCO(C₆-C₁₄-aryl), NHCO(C₆-C₁₄-aryl), N(C₁-C₈-alkyl)CO(C₆-C₁₄-aryl),COO—(C₁-C₈-alkyl), COO—(C₆-C₁₄-aryl), CON(C₁-C₈-alkyl)₂ orCONH(C₁-C₈-alkyl), CONH₂, SO₂NH₂ or SO₂N(C₁-C₈-alkyl)₂.

In a preferred embodiment, the carbocyclic, aromatic substituents areunsubstituted or substituted by up to three identical or differentsubstituents per cycle selected from the group consisting of fluorine,chlorine, C₁-C₈-alkyl, C₁-C₈-fluoro alkyl, C₁-C₈-alkoxy,C₁-C₈-haloalkoxy, C₆-C₁₄-aryl such as phenyl.

In a more preferred embodiment, the carbocyclic, aromatic substituentsare unsubstituted or substituted by up to three identical or differentsubstituents per cycle selected from the group consisting of fluorine,chlorine, C₁-C₄-alkyl, C₁-C₄-perfluoro alkyl, C₁-C₄-alkoxy,C₁-C₄-perfluoroalkoxy and phenyl.

Terms such as C₆-C₁₄ aryl indicate that the number of carbon atoms ofthe respective carbocyclic, aromatic ring system is from 6 to 14 anddoes not take the carbon atoms of potential substituents into account.

As used herein and unless specifically stated otherwise, heterocyclyldenotes heterocyclic aliphatic, aromatic or mixed aliphatic and aromaticsubstituents in which no, one, two or three skeleton atoms per cycle,but at least one skeleton atom in the entire cyclic system is aheteroatom selected from the group consisting of nitrogen, sulphur andoxygen which are unsubstituted or substituted by up to five identical ordifferent substituents per cycle, whereby the substituents are selectedfrom the same group as given above for carbocyclic aromatic substituentsincluding the areas of preference.

Preferred heterocyclyl-substituents and heteroaryl-substituentsrespectively are pyridinyl, oxazolyl, thiophen-yl, benzofuranyl,benzothiophen-yl, dibenzofuranyl, dibenzothiophenyl, furanyl, indolyl,pyridazinyl, pyrazinyl, imidazolyl, pyrimidinyl and quinolinyl, eitherunsubstituted or substituted with one, two or three substituentsselected from the group consisting of fluorine, C₁-C₈-alkyl,C₁-C₈-perfluoro alkyl, C₁-C₈-alkoxy, C₁-C₈-perfluoroalkoxy, and phenyl.

As used herein, and unless specifically stated otherwise, protectedformyl is a formyl substituent which is protected by conversion to anaminal, acetal or a mixed aminal acetal, whereby the aminals, acetalsand mixed aminal acetals are either acyclic or cyclic.

For example, and with preference, protected formyl is1,1-(2,4-dioxycyclopentanediyl).

As used herein, and unless specifically stated otherwise, protectedhydroxyl is a hydroxyl radical which is protected by conversion to aketal, acetal or a mixed aminal acetal, whereby the aminals, acetals andmixed aminal acetals are either acyclic or cyclic. A specific example ofprotected hydroxyl is tetrahydropyranyl (O-THP).

As used herein, and unless specifically stated otherwise, alkyl andalkenyl are straight-chained, cyclic either in part or as a whole,branched or unbranched.

The term C₁-C₁₈-alkyl indicates that the straight-chained, cyclic eitherin part or as a whole, branched or unbranched alkyl substituent containsfrom 1 to 18 carbon atoms excluding the carbon atoms of optionallypresent substituents to the C₁-C₁₈-alkyl substituent. The sameanalogously applies to alkenyl and further substituents having adifferent indicated number or range of carbon atoms if not explicitlystated otherwise.

For the avoidance of doubt the term alkenyl denotes a substituentcomprising at least one carbon-carbon double bond, irrespective of itslocation within the straight-chained, cyclic either in part or as awhole, branched or unbranched substituent.

Specific examples of C₁-C₄-alkyl are methyl, ethyl, n-propyl, isopropyl,n-butyl, tert-butyl. Additional examples for C₁-C₈-alkyl are n-pentyl,cyclohexyl, n-hexyl, n-heptyl, n-octyl, isooctyl. Additional examplesfor C₁-C₁₈-alkyl are norbornyl, adamantyl, n-decyl, n-dodecyl,n-hexadecyl, n-octadecyl.

Specific examples of C₁-C₄-alkoxy-substituents are methoxy, ethoxy,isopropoxy, n-propoxy, n-butoxy and tert-butoxy. An additional examplefor C₁-C₈-alkoxy is cyclohexyloxy.

Specific examples of C₂-C₁₈-alkenyl and C₂-C₈-alkenyl-substituents areallyl, 3-propenyl and buten-2-yl.

As used hereinabove, C₁-C₈-haloalkyl and C₁-C₈-haloalkoxy areC₁-C₈-alkyl and C₁-C₈-alkoxy substituents which are once, more than onceor fully substituted by halogen atoms. Substituents which are fullysubstituted by fluorine are referred to as C₁-C₈-perfluoroalkyl andC₁-C₈-perfluoroalkoxy, respectively.

Specific examples of C₁-C₈-haloalkyl-substituents are trifluoromethyl,2,2,2-trifluoroethyl, chloromethyl, fluoromethyl, bromomethyl,2-bromoethyl, 2-chloroethyl, nonafluorobutyl and n-perfluorooctyl.

The process according to the invention requires employment of compoundsof formulae (II) and (III). Such compounds are commercially available ormay be prepared by published procedures.

In one embodiment

-   R¹ and R² are independently of each other aryl, alkyl or alkenyl    -   whereby the aforementioned alkyl and alkenyl substituents R¹        and/or R² are        -   either not, once, twice or more than twice interrupted by            non-successive functional groups selected from the group            consisting of:        -   —O—, —CO—, —NR⁴(CO)—,        -   and    -   either not, additionally or alternatively either once, twice or        more than twice interrupted by bivalent residues selected from        the group consisting of aryldiyl,        -   and        -   either not, additionally or alternatively either once, twice            or more than twice substituted by substituents selected from            the group consisting of:        -   oxo, fluoro, C₆-C₁₄-aryl; C₁-C₈-alkoxy, —SO₂N(R⁴)₂,            —NR⁴SO₂R⁵, —CO₂N(R⁴)₂, —COR⁴—,            whereby in all formulae where used-   R⁴ is independently selected from the group consisting of hydrogen,    C₁-C₈-alkyl, C₆-C₁₄-aryl or N(R⁴)₂ as a whole is a N-containing    heterocycle,-   R⁵ is independently selected from the group consisting of    C₁-C₈-alkyl, C₆-C₁₄-aryl or N(R⁵)₂ as a whole is a N-containing    heterocycle.

In one embodiment in compounds of formulae (I) and (II)

-   R¹ is C₆-C₁₄-aryl, C₄-C₁₃-heteroaryl or C₁-C₁₈-alkyl, preferably    C₆-C₁₄-aryl, more preferably phenyl.

In one embodiment in compounds of formulae (I) and (III)

-   R² is C₆-C₁₄-aryl or C₄-C₁₃-heteroaryl, preferably C₆-C₁₄-aryl, more    preferably phenyl, mesityl or 2,6-dimethoxyphenyl or naphthyl, and    even more preferably phenyl or mesityl or naphthyl, whereby phenyl    or mesityl are even more preferred.

In one embodiment in compounds of formulae (I) and (II)

-   R^(H) is hydrogen or trimethylsilyl, whereby hydrogen is preferred.

In one embodiment in compounds of formulae (I) and (II)

-   LAF provided that s and x are 1, m is 0 and p is 2, is a q-valent    Lewis Acid

Fragment (LAF) as defined hereinafter including the preferredembodiments for q and the Lewis Acids.

In one preferred embodiment in compounds of formulae (I) and (II)

n is 0

In one preferred embodiment in compounds of formulae (I) and (II)

-   x is 1 or 7 and-   n is 0-   (m+n+p) and thus (m+p) is 3 and    where x is 1 additionally s is 1 and thus (s+m+n+p) is 3 and (m+p)    is 2.

In this embodiment in compounds of formula (I)

-   p is 1 or 2 if x is 1 and is 3 if x is 7 and-   m is 1 or 2 if x is 1, and is 0 if x is 7.

Specific compounds of formula (II) include phosphine (PH₃),tris(trimethylsilyl)phosphine (P(SiMe)₃) andtris(trimethylsilyl)-heptaphosphine ((P₇(SiMe)₃), whereby phosphine ispreferred.

Specific compounds of formula (I) include benzoylphosphine,mesitoylphosphine, naphthoylphosphine, bismesitoylphosphine,dibenzoylphosphine, bisnaphthoylphosphine,dichloroaluminyl-bismesitoylphosphide,difluoroboryl-bismesitoylphosphide,dichloroaluminyl-bisbenzoylphosphide, difluoroboryl-bisbenzoylphosphide,chloroaluminyl-bis(bismesitoylphosphide),chloroaluminyl-bis(bisbenzoyl-phosphide),chloroboryl-bis(bismesitoylphosphide),chloroboryl-bis(bisbenzoyl-phosphide),aluminium-tris(bismesitoylphosphide),aluminium-tris(bisnaphthoylphosphide) and/oraluminium-tris(bisbenzoylphosphide).

Specific compounds of formula (III) include naphthoylchloride,benzoylchloride and mesitoylchloride, whereby benzoylchloride andmesitoylchloride are preferred.

It is known to those skilled in the art that compounds of formula (I) inparticular those comprising a LAF might form oligomers such as dimers ortrimers in solution or solid state depending on solvent or otherconditions. These oligomers shall be encompassed by the invention andthe respective formulae.

The process according to the invention is carried out in the presence ofat least one Lewis acid.

The term “Lewis acid” in the context of the invention is understood tomean the generally customary definition of those compounds which have anelectron vacancy, as explained, for example, in Römpp's Chemie-Lexikon,8^(th) edition, Franck'sche Verlagshandlung 1983, Volume 3, H-L.

In a preferred embodiment the at least one Lewis acid is selected fromthe group including methyl aluminoxane (MAO) and compounds representedby formula (IV)MR^(L) _((r))X_((z-r))  (IV)wherein

-   z is 2, 3, 4 or 5-   r is 0 or an integer of at maximum z, preferably 0, 1 or 2, more    preferably 0 or 1 and even more preferably 0

M if z is 2 is Sn or in another embodiment Sn, Fe, Mn and Zn if z is 3is an element selected from the group consisting of Sc, Y, La, Ce, Pr,Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Fe, B, Al, Ga, In, As if zis 4 is an element selected from the group consisting of V, Ti, Zr, Hf,Sn if z is 5 is an element selected from the group consisting of V, P,As, Sb, Bi

-   X is independently selected from the group consisting of fluoride,    chloride, bromide, iodide, azide, isocyanate, thiocyanate,    isothiocyanate or cyanide, preferably fluoro, chloro or bromo, more    preferably fluoro or chloro-   R^(L) represents C₁-C₁₈-alkyl, cyclopentadienyl, C₁-C₁₈-haloalkyl,    C₁-C₁₈-alkoxy, C₁-C₁₈-haloalkoxy, C₆-C₁₄-aryl, C₇-C₁₈-arylalkyl,    C₆-C₁₄-aryloxy, C₇-C₁₈-arylalkoxy, —O(HC═O), —O(C═O)—(C₁-C₁₈-alkyl),    —O(C═O)—(C₆-C₁₄-aryl) and —O(C═O)—(C₇-C₁₈-arylalkyl) or-   two R^(L) together represent C₄-C₁₈-alkandiyl, C₄-C₁₈-haloalkandiyl,    C₄-C₁₈-alkanedioxy, C₄-C₁₈-haloalkanedioxy, C₆-C₁₄-aryldiyl,    C₇-C₁₈-arylalkanediyl, C₆-C₁₄-aryldioxy, C₇-C₁₈-arylalkanedioxy,    —O(C═O)—(C₁-C₁₈-alkyl)-(C═O)O—, —O(C═O)—(C₆-C₁₄-aryl)-(C═O)O— and    —O(C═O)—(C₇-C₁₈-arylalkyl)-(C═O)O—, or oxo (═O)

In one embodiment r is 0.

For this embodiment examples for such compounds include for

-   z=2 tin dichloride or in another embodiment tin dichloride, zinc    dichloride, iron dichloride and manganese dichloride-   z=3 aluminum trichloride, aluminum tribromide, boron trifluoride,    boron trichloride, boron tribromide, gallium trichloride, indium    trifluoride, scandium trichloride, iron trichloride, arsenic    trifluoride, bismuth trichloride.-   z=4 titanium tetrachloride, titanium tetrabromide, vanadium    tetrachloride, tin tetrachloride, zirconium tetrachloride, hafnium    tetrachloride titanium bromide trichloride, titanium dibromide    dichloride, vanadium bromide trichloride, and tin chloride    trifluoride.-   z=5 antimony pentachloride, antimony pentafluoride, arsenic    pentafluoride, antimony chloride pentafluoride and arsenic fluoride    tetrachloride

Preferred compounds are zinc dichloride, iron dichloride, manganesedichloride, aluminum trichloride and boron trifluoride, whereby aluminumtrichloride and boron trifluoride are preferred.

Those skilled in the art are aware of the fact that lewis acids areoften supplied or available in form of adducts with weak lewis bases, inparticular ethers. Examples thereof include boron trifluoridediethyletherate or tetrahydrofuranate. Such derivatives shall beencompassed by the mere description of the Lewis acids as well.

In one embodiment r is 1, 2 or 3.

For this embodiment examples for such compounds include for

-   z=3 methyl aluminum dibromide, methyl aluminum dichloride, ethyl    aluminum dibromide, ethyl aluminum dichloride, butyl aluminum    dibromide, butyl aluminum dichloride, dimethyl aluminum bromide,    dimethyl aluminum chloride, diethyl aluminum bromide, diethyl    aluminum chloride, dibutyl aluminum bromide, dibutyl aluminum    chloride, methyl aluminum sesquibromide, methyl aluminum    sesquichloride, ethyl aluminum sesquibromide, ethyl aluminum    sesquichloride, methoxyaluminum dichloride, ethoxyaluminum    dichloride, 2,6-di-tert-butylphenoxyaluminum dichloride, methoxy    methylaluminum chloride, 2,6-di-tert-butylphenoxy methylaluminum    chloride, isopropoxygallium dichloride and phenoxy methylindium    fluoride, acetoxyaluminum dichloride, benzoyloxyaluminum dibromide,    benzoyloxygallium difluoride, methyl acetoxyaluminum chloride, and    isopropoyloxyindium trichloride and in one embodiment additionally    triphenylboron.-   z=4 cyclopentadienyltitaniumtrichloride,    dicyclopentadienyltitaniumdichloride,    cyclopentadienylzirconiumtrichloride and    dicyclopentadienylzirconiumdichloride-   z=5 tetraphenylantimony chloride and triphenylantimony dichloride    and vanadium oxytrichloride.

In one embodiment two or more Lewis acids are employed for example twoor three.

As a consequence q-valent Lewis Acids Fragments (LAF) are formallycationic structural units formally obtainable by removing q formallyanionic substituents from a lewis acid. It is apparent for those skilledin the art and understood that depending on the lewis acid employed q isan integer of 1 up to the respective z.

For methyl aluminoxane q is at maximum 3.

Preferred Lewis Acids Fragments (LAF) are structural units of formula(IVa)MR^(L) _((rr))X_((zz-rr))  (IVa)wherein

-   M, X and R^(L) shall have the same meaning including their areas of    preference as described for formula (IV) above-   zz is (z-q) with q being an integer of 1 up to z, wherein z shall    have the same meaning including its areas of preference as described    for formula (IV) above and-   rr is 0 or an integer of at maximum zz, preferably 0, 1 or 2, more    preferably 0 or 1 and even more preferably 0.

Preferred Lewis Acid Fragments (LAF) are

for q=1 (monovalent): dichloroaluminyl AlCl₂ and difluoroboryl BF₂.

for q=2 (divalent): chloroaluminyl AlCl and fluoroboryl BF and

for q=3 (trivalent): aluminum Al.

Those skilled in the art are aware of the fact that the Lewis AcidFragments (LAF) are formally q-times positively charged and that forexample in compounds of formula (Ia) the residue P(OCR²)₂ is formallyanionic with the negative charge being delocated over the five-memberedO—C—P—C—O unit. For reasons of consistency with their analogues having acovalent P—H or P—Si bond instead of an ionic one formulae (I), (Ia) and(IVa) do not specifically indicate the charge distribution or existence.

The process is typically carried out by combining the compounds offormulae (II) and (III) and the at least one Lewis acid either neat ordissolved or suspended in a solvent. Thereby a reaction mixture isformed.

Alternatively the process is carried out by adding the at least oneLewis acid and then the compound of formula (II) either neat ordissolved or suspended in a solvent to a neat compound of formula (III)or a solution or suspension thereof. Thereby a reaction mixture isformed.

The reaction time is typically in the range of from 2 min to 72 hours,preferably 30 min to 24 hours.

Suitable solvents include and preferably are those which do not orvirtually not react under formation of new covalent bonds with thecompounds of formulae (I), (II) and (III).

Such solvents include

-   -   aromatic hydrocarbons and halogenated aromatic hydrocarbons,        such as mesitylene, chlorobenzene and dichlorobenzenes,    -   ethers such as diethylether, methyl tert.butyl ether,        tetrahydrofurane, dioxane, dimethoxyethane, diethoxyethan and        higher glycolethers;    -   amides such as dimethylformamide,    -   sulfones such as tetraethylensulfone,    -   liquid sulfur dioxide and liquid carbon dioxide    -   aliphatic hydrocarbons such as pentane, hexane, cyclohexane,        methylcyclohexane and    -   halogenated aliphatic or olefinic hydrocarbons such as        methylchloride, dimethylchloride, chloroform, trichloroethane        and tetrachloroethene        and mixtures of the aforementioned solvents.

Preferred solvents are halogenated aliphatic hydrocarbons such asmethylchloride, dimethylchloride, chloroform, trichloroethane andtetrachloroethene.

Those skilled in the art are aware that the selection of a suitablesolvent depends inter alia from the solubility and reactivity of thelewis acid(s) employed.

The amount of solvent is not critical at all and is just limited bycommercial aspects, since they have to be removed if the compounds offormula (I) shall finally be isolated.

To facilitate the reaction, mixing energy e.g. by standard agitatorsstirrers and/or static mixing elements is introduced into the reactionmixture.

Even though not necessary, mixing can also be supported by using highforce dispersion devices such as, for example, ultrasound sonotrodes orhigh pressure homogenizers.

The process may either be performed batchwise or continuously.

A typical and preferred reaction temperature range to carry out theprocess is from −30° C. to 120° C., preferably from −10 to 80° C. andeven more preferably from 0 to 40° C.

It is evident to those skilled in the art, that where the desiredreaction temperature is above the boiling point at 1013 hPa of thesolvent employed, the reaction is carried out under sufficient pressure.

A typical and preferred reaction pressure range to carry out the processis from 50 hPa to 10 MPa, preferably from 500 hPa to 1 MPa.

Where phosphine (PH₃) is employed as compound of formula (II) thepreferred reaction pressure range to carry out the process is from 800hPa to 10 MPa, preferably from 1000 hPa to 6 MPa, even more preferablyfrom 1000 hPa to 0.5 MPa.

In one embodiment the reaction is carried out under substantialexclusion of oxygen i.e. an oxygen partial pressure of less than 10 hPa,preferably less than 5 hPa and more preferably less than 0.15 hPa.

A typical and preferred reaction pressure range to carry out the processis from 50 hPa to 10 MPa, preferably from 500 hPa to 1 MPa.

In one embodiment the reaction is carried out under an inert gas i.e. agas that does not or virtually not react with the reactants under thereaction conditions employed.

During the reaction compounds of formula (I) are formed.

The molar ratio of compounds of formula (II) to (III) employed in thereaction depends on the integer m, i.e. the number of acyl groups to befinally present in compounds of formula (I). Typically from 0.8 to 1.2mol of compounds of formula (III) are employed per acyl group to beintroduced, preferably 0.9 to 1.0 mol.

It is known to those skilled in the art that depending on the ratiomolar ratio of compounds of formula (II) to (III) employed in thereaction mixtures of compounds of formula (I) with a varying number ofacyl groups m will be obtained.

The molar ratio of compounds of formula (III) and lewis acid employed inthe reaction is typically from 0.01 to 1 mol of lewis acid per mol ofcompound of formula (III), preferably 0.05 to 1.0 mol, even morepreferably 0.05 to 0.5 mol.

In a particularly preferred embodiment in the process according to theinvention compounds of formula Id) are prepared[LAF]_(s)[P(R^(H))_(m)(COR²)_(p)]_(q)  (Id)wherein

-   [LAF] represents a lewis acid fragment as defined in formula (IVa)    above including its areas of preference at any level-   R^(H) is hydrogen-   R² is C₆-C₁₄-aryl, more preferably phenyl, mesityl or    2,6-dimethoxyphenyl or naphthyl, and even more preferably phenyl or    mesityl or naphthyl, whereby phenyl or mesityl are even more    preferred.-   s is either 0 or, provided that m is 0 and p is 2, s is 1-   q if s is 0, is 1 and    -   if s is 1, is an integer of 1, 2 or 3, more preferably 1 or 3-   m and p are selected such that:    -   m is zero or 1 or 2    -   p is 1 or 2        and the following condition is met:        (m+p) is 3 where s is 0        (m+p) is 2 where s is 1        by reacting phosphine (PH₃) with compounds of formula (III)        R²COHal  (III)        wherein R² is as defined above and-   Hal represents fluoro, chloro, bromo or iodo, preferably chloro or    bromo and even more preferably chloro    whereby the reaction is carried out in the presence of at least one    lewis acid of formula (IV) as defined above including its areas of    preference at any level.

It was found that where phosphine (PH₃) is employed, with increasingamounts of Lewis acid compounds of formula (Ia) may be formed as majorproduct.[LAF][P(COR²)₂]_(q)  (Ia)

The compounds of formula (Ia) are novel with the exception of thefollowing compounds:

-   1) diphenylboryldipivaloylphosphide since this compound is known    from A. S. Ionkin, L. F. Chertanova, B. A. Arbuzov, Phosphorus,    Sulfur and Silicon and the Related Elements 1991, 55, 133-136.-   2) 1-oxa-3-oxonia-5λ³-phospha-2-borata-4,6-dimethylcyclohexadiene    and 1-oxa-3-oxonia-5λ³-phospha-2-borata-4,6-diphenylcyclohexadiene    since these compounds are known from H. Noth, S. Staude, M.    Thomann, J. Kroner, R. T. Paine, Chem. Ber. 1994, 127, 1923-1926:

with R=methyl or phenyl

The preferred substitution pattern disclosed above for compounds offormula (I), the LAFs and R² is likewise applicable here.

As shown for two of the excluded compounds above and as confirmed by theinventors of the present invention the structure of compounds of formula(Ia) e.g. for q=1 is best illustrated by the following general formula(Ib) and its mesomeric analogues:

Simply for avoidance of doubt these structures shall of course beencompassed by the more general formula (Ia).

Specific examples of compounds of formulae (I) and (Ia) aredichloroaluminyl-bismesitoylphosphide,chloroaluminyl-bis(bismesitoylphosphide), chloroaluminyldifluoroboryl-bismesitoylphosphide-bis(bisbenzoylphosphide),chloroboryl-bis(bismesitoylphosphide),chloroboryl-bis(bisbenzoylphosphide),aluminium-tris(bismesitoylphosphide)aluminium-tris(bisnaphthoylphosphide) andaluminium-tris(bisbenzoylphosphide), wherebydifluoroboryl-bismesitoylphosphide, aluminium-tris(bismesitoylphosphide)and aluminium-tris(bisbenzoylphosphide) are preferred.

Compounds of formula (Ia) may be converted to compounds where the LAF isreplaced by hydrogen.

Therefore, the invention further encompasses a process for preparingcompounds of formula (Ib)HP(COR²)₂  (Ib)by reacting compounds of formula (Ia) with a proton source.

In one embodiment proton sources include water, acids and alcohols or amixture thereof. Suitable acids include those having a pKa of 7 or less,preferably 5 or less, more preferably 2 or less at 25° C. and measuredin water.

Examples of suitable acids include hydrogen chloride in water or indiethylether, sulphuric acid, carboxylic acids such as formic acid,acetic acid and citric acid and Alcohols such as ethyleneglycol.

In one embodiment water is employed for the aforementioned conversion.In another embodiment toluene is employed for the aforementionedconversion.

The amount of the proton source is not critical and might be in therange of from 0.1 to 100 mol equivalents with respect to the compoundsof formula (I), preferably in the range of from 0.9 to 1.2 molequivalents.

Compounds or formula (I) and in particular those wherein x=1 or those offormula (Ia) and (Ib) are useful as precursor materials for substitutedbisacylphosphine oxides, whether polymeric or not, which are versatilephotoinitiators.

Such bisacylphosphine oxides be obtained by reaction of compounds offormula (I) in a manner known per se in the art and disclosed forexample in WO2006/056541 and WO2014/053455 which are herein incorporatedby reference in their entirety.

Thus, compounds of formula (I) and (Ia) and (Ib) are particularly usefulas precursors for photoinitiators. Therefore, one further aspect of theinvention relates to the use of compounds of formula (I) or (Ia) or (Ib)in a process for the preparation of photoinitiators.

Another aspect of the invention relates to a process for preparingbisacylphosphinoxides comprising the process for preparing compounds offormula (I) and optionally (Ib) as disclosed above.

The invention is further illustrated by the examples without beinglimited thereby.

EXAMPLES I Materials and Methods

All reactions were carried out under argon using either standard Schlenktechniques or an argon-filled glove box. Solvents were purified using anInnovative Technology PureSolv MD 7 solvent purification system. Allreagents were used as received from commercial suppliers unlessotherwise stated. The compounds Na₃P₇ and (Me₃Si)₃P₇ were synthesizedfollowing literature procedures, e.g. M. Cicač-Hudi, J. Bender, S. H.Schlindwein, M. Bispinghoff, M. Nieger, H. Grützmacher, D. Gudat, Eur.J. Inorg. Chem. 2015, 5, 649. X-ray single crystal diffraction studieswere performed on an Oxford XCalibur S diffractometer equipped with amolybdenum X-ray tube (λ=0.7107 Å).

II General Methods for the Preparation of Acylphosphines Example 1aAcylation of PH₃ with Mesitoyl Chloride in the Presence of BF₃.Et₂O

A 100 mL two neck round bottom flask containing mesitoylchloride(MesCOCl) (4 mL, 24 mmol, 1 eq.) and boron trifluoride etherate(BF₃.Et₂O) (0.15 mL, 1.2 mmol, 0.05 eq.) in dichloromethane (DCM) (20mL) was connected via one neck to the PH₃ supply and via the other neckto a bleach scrubber. The flask was flushed with PH₃, then the stopcockto the bleach scrubber was closed and the system pressurized with 50 kPaPH₃. Typically, the PH₃ consumption was finished after 3 to 6 hours. Theflask was stirred for another 12 h at 20° C. Then the system was openedto the bleach scrubber and flushed with argon for 30 min to remove alltraces of PH₃. The crude reaction mixture was analyzed by ³¹P-NMRspectroscopy. Based on the integrals of the NMR signals, the mixture wasfound to contain 70% bis(mesitoylphosphine) HP(COMes)₂ [δ(³¹P)=89.2 (s,enol), 2.2 (d, ¹J_(PH)=246.8 Hz, keto) ppm], 16%difluoroborylbis(mesitoylphosphide) [BF₂]P(COMes)₂ [δ(³¹P)=93.4 (s) ppm]and 14% mono(mesitoylphosphine) H₂P(COMes) [δ(³¹P)=−97.4 (t,¹J_(PH)=218.3 Hz) ppm]. MesCOCl (0.33 mL, 2.0 mmol) and BF₃.Et₂O (0.013mL, 0.10 mmol) were again added and the mixture stirred for another 60min. Subsequently, the mixture was analyzed by ³¹P-NMR spectroscopy andfound to contain 76% HP(COMes)₂ and 16% [BF₂]P(COMes)₂. Degassed water(25 mL) was added and the suspension stirred for 24 h at 20° C. Theaqueous phase was extracted with DCM (3×5 mL). The solvent was removedunder reduced pressure from the combined organic phases, yieldingHP(COMes)₂ as a bright yellow crystalline solid. The analytical datacorresponded to published data.

Example 1b Acylation of PH₃ with Mesitoyl Chloride in the Presence ofBF₃.Et₂O

A steel autoclave fitted with a 100 mL ceramic cell containingmesitoylchloride (MesCOCl) (4 mL, 24 mmol, 1 eq.) and boron trifluorideetherate (BF₃.Et₂O) (0.15 mL, 1.2 mmol, 0.05 eq.) in dichloromethane(DCM) (20 mL) was connected via an inlet to the PH₃ supply and via anoutlet to to a bleach scrubber. The autoclave was flushed with PH₃ andthen the valve to the bleach scrubber was closed and the systempressurized with 250 kPa PH₃. Typically, the PH₃ consumption wasfinished after 3 to 6 hours. The flask was stirred for another 12 h at20° C. Then the system was opened to the bleach scrubber and flushedwith argon for 30 min to remove all traces of PH₃. The crude reactionmixture was analyzed by ³¹P-NMR spectroscopy. Based on the integrals ofthe NMR signals, the mixture was found to be substantially identical tothe one obtained in example 1a).

Example 2 Acylation of (Me₃Si)₃P₇ with Mesitoyl Chloride in the Presenceof BF₃.Et₂O

To a solution of MesCOCl (2.48 mL, 15 mmol, 6 eq.) and BF₃.Et₂O (0.95mL, 7.5 mmol, 3 eq.) in DCM (10 mL) was added solid tris(trimethylsilyl)heptaphosphide (Me₃Si)₃P₇ (1.09 g, 2.5 mmol, 1 eq.). The orange solutionwas stirred for 16 h and the solvent removed under reduced pressure toobtain (MesCO)₃P₇ as a bright yellow solid (1.63 g, 2.48 mmol, 99%). Ananalytically pure sample could be obtained by layering a saturated THFsolution with hexane, collecting the yellow crystalline on a glass fritand drying it under reduced pressure.

Mp 198-199° C. (from THF). Analysis Found: C, 55.7; H, 5.5; N, 0.2.Calc. for C₃₀H₃₃O₃P₇: C, 54.7; H, 5.1; N, 0.0. ¹H-NMR (300 MHz, CD₂Cl₂):δ=6.85 (s, 6H, Ar), 2.30 (s, 9H, CH₃), 2.24 (s, 18H, CH₃) ppm. ³¹P-NMR(CDCl₃, 121 MHz): δ=135.0 to 122.0 (m, 3P), −140.0 to −151.0 (m, 1P),−148.5 to −159.5 (m, 3P) ppm.

Example 3 Acylation of PH₃ with Mesitoyl Chloride in the Presence ofAlCl₃ Yielding Aluminum tris[bis(mesitoyl)phosphide][Al(^(Mes)BAP)₃]

A 100 mL round bottom flask with two Normag spindle valves was chargedwith MesCOCl (6 eq., 90 mmol, 15.0 mL), AlCl₃ (1 eq., 15 mmol, 2.00 g)and tetrachloroethene C₂Cl₄ (35 mL). One side of the flask was connectedto a PH₃ gas bottle and the other side to a series of three bleachbathes. The system was purged with argon for 15 min to remove traces ofoxygen. Then it was pressurized with 80 kPa PH₃ under vigorous stirring.An incipient pressure drop was followed by a pressure rise to about 120kPa due to the formation of HCl as by-product. The system was opened tothe bleach bath and pressurized with PH₃ again. This procedure wasrepeated several times until the pressure remained stable. The orangesuspension was stirred for another 16 h under 80 kPa PH₃ pressure,before it was opened to the bleach bath and purged with argon for 60min. The suspension was transferred to a 100 mL round bottom Schlenkflask and the solvent removed to a minimum under reduced pressure.Precipitation of the product was completed by addition of n-hexane (50mL). The product was collected on a G3 glass frit, washed with n-hexane(3×10 mL) and dried under reduced pressure, yielding the aluminumcomplex [Al(^(Mes)BAP)₃] as a bright orange powder (14.0 g, 14.0 mmol,93%).

Mp 137-139° C. ¹H-NMR (300 MHz, CDCl₃): δ=6.73 (s, 12H, Ar), 2.24 (s,18H, CH₃), 2.15 (s, 36H, CH₃) ppm. ¹³C{¹H}-NMR (75 MHz, CDCl₃): δ=229.0(d, ¹J_(PC)=88.2 Hz, C(O)P), 140.0 (d, ²J_(PC)=27.9 Hz, C_(ipso), 138.4(s, C_(para)), 134.0 (d, C_(ortho)), 128.3 (s, C_(meta)), 21.2 (s, CH₃),19.6 (s, CH₃) ppm. ³¹P-NMR (CDCl₃, 121 MHz): δ=99.0 (s) ppm.

Example 4 Acylation of PH₃ with Benzoyl Chloride in the Presence ofAlCl₃ Yielding Aluminum tris[bis(benzoyl)phosphide] [Al(^(Ph)BAP)_(3])

A 100 mL round bottom flask with two Normag spindle valves was chargedwith benzoylchloride (PhCOCl, 6 eq., 17.4 mmol, 2.00 mL), AlCl₃ (1 eq.,2.90 mmol, 290 mg) and tetrachloroethene C₂Cl₄ (10 mL). Reaction andwork-up were carried out as described above, yielding the aluminumcomplex [Al(^(Ph)BAP)₃] as a bright red powder (1.35 g, 1.80 mmol, 62%).

³¹P-NMR (CDCl₃, 121 MHz): δ=68.7 (s) ppm.

Example 5 Synthesis of bis(mesitoyl)phosphine HP(COMes)₂ from[Al(^(Mes)BAP)₃]

A suspension of the aluminum complex [Al(^(Mes)BAP)₃] prepared accordingto example 3 (1 eq, 0.100 mmol, 100 mg) and citric acid (2 eq., 0.200mmol, 38 mg) in toluene (2.0 mL) was refluxed for 6 hours. The resultingyellow suspension was filtered over a G3 glass frit and the solvent ofthe filtrate removed under reduced pressure, yieldingbis(mesitoyl)phosphine HP(COMes)₂ as a bright yellow powder (90 mg,0.275 mmol, 92%).

¹H-NMR (300 MHz, C₆D₆): δ=19.3 (d, ³J_(PH)=2.0 Hz, OHO), 6.63 (s, Ar),6.63 (s, Ar), 5.44 (d, ¹J_(PH)=244.2 Hz, PH), 2.34 (s, CH₃), 2.18 (s,CH₃), 2.03 (s, CH₃), 2.00 (s, CH₃) ppm. ³¹P-NMR (CDCl₃, 121 MHz): δ=90.2(s, enol), 3.8 (d, ¹J_(PH)=243.6 Hz, keto) ppm.

Example 6 Synthesis of bis(benzoyl)phosphine HP(COPh)₂ from[Al(^(Ph)BAP)₃]

A suspension of the aluminum complex [Al(^(Ph)BAP)₃] (1 eq, 0.100 mmol,75 mg) prepared according to example 4 and citric acid (2 eq., 0.200mmol, 38 mg) in toluene (2.0 mL) was refluxed for 2.5 hours. Theresulting orange suspension was filtered over a G3 glass frit and thesolvent of the filtrate removed under reduced pressure, yieldingbis(benzoyl)phosphine HP(COPh)₂ as a bright orange powder (70 mg, 0.289mmol, 96%).

¹H-NMR (300 MHz, C₆D₆): δ=20.1 (d, ³J_(PH)=3.1 Hz, OHO), 8.20-8.10 (s,4H, Ar), 7.12-6.95 (s, 6H, Ar) ppm. ¹³C{¹H}-NMR (75 MHz, C₆D₆): δ=228.3(d, ¹J_(PC)=86.1 Hz, C(O)P), 140.1 (d, ²J_(PC)=26.7 Hz, C_(ipso)), 144.0(d, ⁵J_(PC)=2.8 Hz, C_(para)), 128.9 (s, C_(meta)), 126.5 (d,³J_(PC)=16.7 Hz, C_(ortho)) ppm. ³¹P-NMR (CDCl₃, 121 MHz): δ=90.2 (s,enol), 3.8 (d, ¹J_(PH)=243.6 Hz, keto) ppm.

Example 7a Synthesis of difluoroboryl-bismesitoylphosphide[BF₂(^(Mes)BAP)] from PH₃

A 100 mL two neck round-bottom flask containing mesitoylchloride(MesCOCl) (5.0 mL, 30 mmol, 1 eq.) and boron trifluoride diethyletherate (BF₃.Et₂O, 2.38 mL, 18.8 mmol, 1 eq.) in C₂Cl₄ (20 mL) wasexposed to 800 hPa PH₃ for 48 h. After purging the system, the orangesuspension was transferred to a Schlenk flask with, the solventevaporated to a minimum and precipitation of the product completed byaddition of n-hexane (40 mL). The product was collected on a glass frit,washed with n-hexane (3×5 mL) and dried under reduced pressure, yieldingthe boron complex difluoroboryl-bismesitoylphosphide [BF₂(^(Mes)BAP)] asa yellow solid (3.90 g, 10.4 mmol, 69%). Single crystals were obtainedfrom toluene at −30° C.

¹H-NMR (300 MHz, CDCl₃): δ=6.93 (s, 3H, Mes-H), 2.37 (s, 12H, CH₃), 2.32(s, 6H, CH₃) ppm. ¹³C{¹H}-NMR (300 MHz, CDCl₃): δ=237.7 (dt,¹J_(PC)=95.0, ³J_(BC)=2.2 Hz, C(O)P), 141.6 (d, J=1.4 Hz, p-Mes), 135.4(d, ³J_(PC)=3.7 Hz, o-Mes), 135.3 (d, ²J_(PC)=21.2 Hz, ipso-Mes), 129.4(s, m-Mes), 21.3 (s, p-CH₃), 20.1 (d, ⁴J_(PC)=3.8 Hz, o-CH₃) ppm.³¹P-NMR (121 MHz, CDCl₃): δ=94.3 (s) ppm.

Example 7b Synthesis of bis(mesitoyl)phosphine HP(COMes)₂ fromdifluoroboryl-bismesitoylphosphide [BF₂(^(Mes)BAP)]

A solution of the boron complex [BF₂(^(Mes)BAP)] (1.33 g, 3.55 mmol) inTHF (15 mL) and water (2 mL) was stirred for 15 min at 20° C. Volatileswere removed from the bright yellow solution under reduced pressure,yielding the phosphine ^(Mes)BAP-H as a bright yellow powder (1.16 g,3.55 mmol, 100%).

Example 8 Acylation of PH₃ with neat mesitoyl chloride in the presenceof AlCl₃ Yielding Aluminum tris [bis(mesitoyl)phosphide][Al(^(Mes)BAP)₃]

A 100 mL round-bottom flask with two Normag spindle valves was chargedwith mesitoylchloride (10.0 mL, 60.0 mmol, 4 eq.) and AlCl₃ (333 mg,2.50 mmol, 1 eq.). The reaction and the workup were carried out asdescribed in example 3, yielding the aluminum complex [Al(^(Mes)BAP)₃]as a bright orange powder (2.38 g, 2.37 mmol, 95%, corresponding toAlCl₃)

¹H-NMR (300 MHz, CDCl₃): δ=6.75 (s, 12H, Mes-H), 2.25 (s, 18H, CH₃),2.17 (s, 36H, CH₃) ppm.

¹³C{¹H}-NMR (75 MHz, CDCl₃): δ=240.3 (d, ¹J_(PC)=92.2 Hz, C(O)P), 140.0(d, ²J_(PC)=28.0 Hz, ipso-Mes, 138.4 (d, ⁵J_(PC)=1.3 Hz, p-Mes), 134.0(d, ³J_(PC)=3.0 Hz, o-Mes), 128.3 (s, m-Mes), 21.2 (s, p-CH₃), 19.6 (d,⁴J_(PC)=2.7 Hz, o-CH₃) ppm.

³¹P-NMR (121 MHz, CDCl₃): δ=99.0 (s) ppm.

Analysis Found C, 71.0; H, 6.7; N, 0.1. Calc. for C₆₀H₆₆O₆P₃Al: C, 71.8;H, 6.6; N, 0. Mp>180° C. (decomposition, from toluene).

Example 9 Acylation of PH₃ with 1-naphthoyl Chloride in the Presence ofAlCl₃ Yielding Aluminum tris [bis(naphthoyl)phosphide] [Al(^(Naph)BAP)₃]

A thick walled 100 mL round bottomed flask with two Normag taps wascharged with anhydrous AlCl₃ (333 mg, 2.5 mmol) in a glovebox. To this1-naphthoyl chloride (2.26 mL, 15 mmol) and C₂Cl₄ (10 mL) were added.The mixture was placed under 1 bar Ar to check for leaks. The mixturewas then stirred for 30 minutes, and a pale yellow solution formed. TheAr pressure was released and the flask repressurised with 800 hPa PH₃,an orange colour was immediately observed. After 1 hour the atmospherewas replaced with fresh PH₃ to remove any HCl formed. The mixture wasvigorously stirred over the weekend (3 nights) and turned bright orange,with the formation of a bright orange precipitate. A ³¹P NMR spectrumshowed the solution to be complete. The reaction mixture was thentransferred into a Schlenk flask with THF (40 mL). The solution wasconcentrated to approximately 10 mL and then hexane (20 mL) added tocomplete the precipitation. This was then filtered under Ar and thesolid washed with a hexane (20 mL). The solid was dried on the fritunder vacuum and collected to yield Al(^(Naph)BAP)₃ as a bright orangesolid (1.947 g, 74%).

Example 10 Acylation of PH₃ with Mesitoyl Chloride in the Presence ofZnCl₂

A thick walled 100 mL round bottomed flask with two Normag taps wascharged with anhydrous ZnCl₂ (340.7 mg, 2.5 mmol) in a glovebox. To thismesitoyl chloride (1.66 mL, 10 mmol) and C₂Cl₄ (10 mL) were added. Themixture was placed under 1 bar Ar and then stirred for 15 minutes, and apale yellow colour observed with partial dissolving of the ZnCl₂. The Arpressure was released and the flask repressurised with 800 hPa PH₃.After 1 hour the atmosphere was replaced with fresh PH₃ to remove anyHCl formed. The mixture was vigorously stirred overnight and turned adarker yellow, and some yellow precipitate was observed on the flaskwalls. A ³¹P NMR spectrum showed the solution to contain both HP(COMes)₂and H₂P(COMes) in a ratio of approximately 1:1. The reaction mixture wasagain pressurised with PH₃ and left over the weekend (3 nights), the ³¹PNMR now showed approximately 90% HP(COMes)₂. The reaction mixture wasthen transferred into a Schlenk flask with THF (20 mL). The solution wasconcentrated to approximately 10 mL and then hexane (10 mL) added tocomplete the precipitation. This was then filtered under Ar and thefiltrate then dried under vacuum to yield a sticky yellow solid (1.55g). This was then washed with dry hexane (5 mL) to yield a yellowpowder, the supernatant was removed by cannula filtration and the powderdried to yield HP(COMes)₂ (0.872 g, 2.67 mmol, 53%).

Example 11 Acylation of PH₃ with Naphthoyl Chloride (NaphCOCl) in thePresence of ZnCl₂

A thick walled 100 mL round bottomed flask with two Normag taps wascharged with anhydrous ZnCl₂ (340.7 mg, 2.5 mmol) in a glovebox. To this1-naphthoyl chloride (1.5 mL, 10 mmol) and C₂Cl₄ (10 mL) were added. Themixture was placed under 1 bar Ar and then stirred for 30 minutes, and apale yellow colour was observed with partial dissolving of the ZnCl₂.The Ar pressure was released and the flask repressurised with 800 hPaPH₃, and an orange colour was immediately observed. After 1 hour theatmosphere was replaced with fresh PH₃ to remove any HCl formed. Themixture was vigorously stirred over the weekend (3 nights) and turnedbright orange, with a bright orange precipitate observed. A ³¹P NMRspectrum showed the solution to contain both HP(CONaph)₂ and H₂P(CONaph)in a ratio of approximately 1:1. The reaction mixture was then left tostir under Ar for a further 2 days and no H₂P(CONaph) was visible in the³¹P NMR spectrum. The reaction mixture was then transferred into aSchlenk flask with Toluene (20 mL) and THF (5 mL). The solution wasconcentrated to approximately 10 mL and then hexane (10 mL) added tocomplete the precipitation. This was then filtered under Ar and thefiltrate then dried under vacuum to yield a sticky orange product. Thiswas then dissolved in dry hexane (40 mL) and filtered, the hexane wasremoved under vacuum to yield a bright orange oil.

Example 12 Acylation of PH₃ with Naphthoyl Chloride (NaphCOCl) in thePresence of TiCl₄

TiCl₄ (1 M in Tol, 2.5 mL, 2.5 mmol) was diluted with dry toluene (7.5mL) in a thick walled 100 mL round bottomed flask with two Normag tapsunder Ar. To this 1-naphthoyl chloride (1.5 mL, 10 mmol) was added, thecolour changed from a pale orange to a dark red. The mixture was placedunder 1 bar Ar and then stirred for 15 minutes. The Ar pressure wasreleased and the flask repressurised with 800 hPa PH₃. The atmospherewas exchanged with fresh PH₃ twice more; once after 1 hour and a secondtime after 2 hours. The reaction was stirred overnight, 16 hours. Thecolour changed from red to green/black in this time. When degassed waterwas added to the green/black solution, it turned orange and theformation of HP(CONaph)₂ was observed in ³¹P NMR. When dry hexane wasadded to the solution, a bronze/red precipitate was obtained.

Example 13 Acylation of PH₃ with Mesitoyl Chloride in the Presence ofFeCl₃

A thick walled 100 mL round bottomed flask with two Normag taps wascharged with anhydrous FeCl₃ (406 mg, 2.5 mmol) in a glovebox. To thismesitoyl chloride (2.45 mL, 15 mmol) and C₂Cl₄ (10 mL) were added. Themixture was placed under 1 bar Ar and then stirred for 15 minutes, and apale yellow solution was observed above a sticky brown solid. The Arpressure was released and the flask repressurised with 800 hPa PH₃.After 1 hour the atmosphere was replaced with fresh PH₃ to remove anyHCl formed, this was repeated once more. The mixture was vigorouslystirred over a weekend. A ³¹P NMR spectrum showed a multitude of peaks,including δ (ppm) 90.4 and −95.7 (t, ¹J_(PH)=212 Hz) which areassignable to HP(COMes)₂ and H₂P(COMes) respectively.

Example 14 Acylation of PH₃ with Mesitoyl Chloride in the Presence ofMnCl₂

A thick walled 100 mL round bottomed flask with two Normag taps wascharged with anhydrous MnCl₂ (315 mg, 2.5 mmol) in a glovebox. To thismesitoyl chloride (1.66 mL, 10 mmol) and toluene (10 mL) were added. Themixture was placed under 1 bar Ar and then stirred for 15 minutes, and apale yellow solution was observed above a pinkish solid. The Ar pressurewas released and the flask repressurised with 800 hPa PH₃. After 1 hourthe atmosphere was replaced with fresh PH₃ to remove any HCl formed,this was repeated once more. The mixture was vigorously stirred for 20hours. A ³¹P NMR spectrum showed the presence of HP(COMes)₂ andH₂P(COMes). The MnCl₂ was filtered off and the solvent of the filtratewas removed under vacuum to yield a sticky yellow solid. The solid waswashed by adding hexane (1 mL) and stirring overnight. The yellow solidwas then collected by filtration and dried under vacuum to yieldHP(COMes)₂ (0.98 g, 3 mmol, 60%).

Example 15 Acylation of PH₃ with Mesitoyl Chloride in the Presence ofFeCl₂

Example 15 was carried out as example 14 with the only difference beingthat FeCl₂ (318 mg, 2.5 mmol) was used instead of MnCl₂. HP(COMes)₂ wasobtained in a yield of 58%.

Example 16 Acylation of PH₃ with Mesitoyl Chloride in the Presence ofMethylaluminoxane (MAO)

To a solution of mesitoyl chloride (4.0 mL, 24 mmol) in dichloromethane(15 mL) was added a solution of methyl aluminumoxane in toluene (1.0 mL,0.895 g mL⁻¹, 7 wt-% Al, 2.4 mmol Al, 0.1 eq.). The resulting darkorange solution was exposed to 800 hPa PH₃ for 48 h. The ³¹P-NMRspectrum showed a broad signal at δ=100 ppm, which can be assigned to amixture of different Al-complexes of HP(COMes)₂. After addition of H₂O₂(8.0 mL, 30 wt-%, 72 mmol, 3.0 eq.) at 0° C., a sharp signal at δ=−2 ppmwas observed in the ³¹P-spectrum, which can be assigned to(HO)OP(COMes)₂.

The invention claimed is:
 1. Compounds of formula (Ia)[LAF][P(COR²)₂]_(q)  (Ia) wherein: LAF represents a q-valent Lewis AcidFragment (LAF) that is a cationic structural unit obtainable by removingq anionic substituents from a Lewis acid, q is an integer of 1 to 5, andR² is aryl or heterocyclyl alkyl or alkenyl whereby the aforementionedalkyl and alkenyl substituent R² is either not, once, twice or more thantwice interrupted by non-successive functional groups selected from thegroup consisting of: —O—, —NR⁴—, —CO—, —OCO—, —O(CO)O—, NR⁴(CO)—,—NR⁴(CO)O—, O(CO)NR⁴—, —NR⁴(CO)NR⁴—, and either not, additionally oralternatively either once, twice or more than twice interrupted bybivalent residues selected from the group consisting ofheterocyclo-diyl, and aryldiyl, and either not, additionally oralternatively either once, twice or more than twice substituted bysubstituents selected from the group consisting of: oxo, halogen, cyano,C₆-C₁₄-aryl; heterocyclyl, C₁-C₈-alkoxy, C₁-C₈-alkylthio, —SO₂N(R⁴)₂,—NR⁴SO₂R⁵, —N(R⁴)₂—, —CO₂N(R⁴)₂, —COR⁴—, OCOR⁵, —O(CO)OR⁵, NR⁴(CO)R⁴,—NR⁴(CO)OR⁴, O(CO)N(R⁴)₂, —NR⁴(CO)N(R⁴)₂, whereby in all formulae whereused R⁴ is independently selected from the group consisting of hydrogen,C₁-C₈-alkyl, C₆-C₁₄-aryl, and heterocyclyl, or N(R⁴)₂ as a whole is aN-containing heterocycle, and R⁵ is independently selected from thegroup consisting of C₁-C₈-alkyl, C₆-C₁₄-aryl, and heterocyclyl, orN(R⁵)₂ as a whole is a N-containing heterocycle, with the exception ofdiphenylboryldipivaloylphosphide and1-oxa-3-oxonia-5λ³-phospha-2-borata-4,6-dimethylcyclohexadiene and1-oxa-3-oxonia-5λ³-phospha-2-borata-4,6-diphenylcyclohexadiene:

with R=methyl or phenyl.
 2. Compounds according to claim 1, wherein R²is C₆-C₁₄-aryl or C₄-C₁₃-heteroaryl.
 3. Compounds according to claim 1,wherein LAF is dichloroaluminyl (AlCl₂) or difluoroboryl (BF₂) with qbeing 1 chloroaluminyl (AlCl) or fluoroboryl (BF) with q being 2 oraluminum (Al) or boron (B) with q being
 3. 4. The following compounds offormula (Ia) according to claim 1:dichloroaluminyl-bismesitoylphosphide,difluoroboryl-bismesitoylphosphide,dichloroaluminyl-bisbenzoylphosphide, difluoroboryl-bisbenzoylphosphide,chloroaluminyl-bis(bismesitoylphosphide),chloroaluminyl-bis(bisbenzoylphosphide),chloroboryl-bis(bismesitoylphosphide),chloroboryl-bis(bisbenzoyl-phosphide),aluminium-tris(bismesitoylphosphide),aluminium-tris(bisnaphthoylphosphide) and/oraluminium-tris(bisbenzoylphosphide).
 5. Compounds according to claim 1,wherein LAF is obtainable from a Lewis acid selected from the groupconsisting of methyl aluminoxane (MAO) and compounds represented byformula (IV)MR^(L) _((r))X_((z-r))  (IV) wherein z is 2, 3, 4 or 5 r is 0 or aninteger of at maximum z M if z is 2 is an element selected from thegroup consisting of Sn, Zn, Fe, and Mn if z is 3 is an element selectedfrom the group consisting of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy,Ho, Er, Tm, Yb, Lu, Fe, B, Al, Ga, In, and As if z is 4 is an elementselected from the group consisting of V, Ti, Zr, Hf, and Sn if z is 5 isan element selected from the group consisting of V, P, As, Sb, and Bi Xis independently selected from the group consisting of fluoride,chloride, bromide, iodide, azide, isocyanate, thiocyanate,isothiocyanate, and cyanide R^(L) represents C₁-C₁₈-alkyl,C₁-C₁₈-haloalkyl, C₁-C₁₈-alkoxy, C₁-C₁₈-haloalkoxy, C₆-C₁₄-aryl,C₇-C₁₈-arylalkyl, C₆-C₁₄-aryloxy, C₇-C₁₈-arylalkoxy, —O(HC═O),—O(C═O)—(C₁-C₁₈-alkyl), —O(C═O)—(C₆-C₁₄-aryl) or—O(C═O)—(C₇-C₁₈-arylalkyl) or two R^(L) together representC₄-C₁₈-alkandiyl, C₄-C₁₈-haloalkandiyl, C₄-C₁₈-alkanedioxy,C₄-C₁₈-haloalkanedioxy, C₆-C₁₄-aryldiyl, C₇-C₁₈-arylalkanediyl,C₄-C₁₈-alkanedioxy, C₄-C₁₈-haloalkanedioxy, C₆-C₁₄-aryl)-(C═O)O—,(C₁-C₁₈-alkyl)-(C═O)O—, —O(C═O)—(C₆-C₁₄-aryl)-(C═O)O—,—O(C═O)—(C₇-C₁₈-arylalkyl)-(C═O)O—, or oxo (═O).
 6. Compounds accordingto claim 5, wherein LAF is a structural unit of formula (IVa)MR^(L) _((rr))X_((zz-rr))  (IVa) wherein M, X and R^(L) have the samemeaning as described for formula (IV) zz is (z-q) with q being aninteger of 1 up to z, wherein z has the same meaning as described forformula (IV) and rr is 0 or an integer of at maximum zz.
 7. A processfor the preparation of compounds of formula (I):[LAF]_(s)[P_(x)(R^(H))_(m)(R¹)_(n)(COR²)_(p)]_(q)  (I) wherein s iseither 0 or, provided that x is 1, m and n are 0 and p is 2, s is 1 q ifs is 0, is 1 and if s is 1, is an integer of 1 to 5 x is an integer of 1to 15 or 20 m, n and p are selected such that: m is zero or an integerof 1 or more n is zero or an integer of 1 or more P is an integer of 1or more and one of the following conditions is met: If x is an integerof 1 to 9 (m+n+p) is (x+2) where s is 0 (m+n+p) is (x+1) where s is 1 xis an integer of 3 to 10 (m+n+p) is x x is an integer of 4 to 12 (m+n+p)is (x−2) x is an integer of 5 to 10 or 13 (m+n+p) is (x−4) x is aninteger of 7 to 14 (n+m+p) is (x−6) x is 10, 11 or 15 (m+n+p) is (x−8) x= is 12 or 20 (m+n+p) is (x−10)

LAF represents a q-valent Lewis Acid Fragment (LAF) that is a cationicstructural unit obtainable by removing q anionic substituents from aLewis acid, R^(H) are independently of each other either hydrogen, or aresidue of formula Si(R³)₃, wherein the substituents R³ areindependently of each other selected from the group consisting ofC₁-C₁₈-alkyl and C₆-C₁₄-aryl R¹ and R² are independently of each otheraryl or heterocyclyl, alkyl or alkenyl whereby the aforementioned alkyland alkenyl substituents R¹ and/or R² are either not, once, twice ormore than twice interrupted by non-successive functional groups selectedfrom the group consisting of: —O—, —NR⁴—, —CO—, —OCO—, —O(CO)O—,NR⁴(CO)—, —NR⁴(CO)O—, O(CO)NR⁴—, —NR⁴(CO)NR⁴—, and either not,additionally or alternatively either once, twice or more than twiceinterrupted by bivalent residues selected from the group consisting ofheterocyclo-diyl, and aryldiyl, and either not, additionally oralternatively either once, twice or more than twice substituted bysubstituents selected from the group consisting of: oxo, halogen, cyano,C₆-C₁₄-aryl; heterocyclyl, C₁-C₈-alkoxy, C₁-C₈-alkylthio, —SO₂N(R⁴)₂,—NR⁴SO₂R⁵, —N(R⁴)₂—, —CO₂N(R⁴)₂, —COR⁴—, —OCOR⁵, —O(CO)OR⁵, NR⁴(CO)R⁴,—NR⁴(CO)OR⁴, O(CO)N(R⁴)₂, —NR⁴(CO)N(R⁴)₂, whereby in all formulae whereused R⁴ is independently selected from the group consisting of hydrogen,C₁-C₈-alkyl, C₆-C₁₄-aryl, and heterocyclyl or N(R⁴)₂ as a whole is aN-containing heterocycle, R⁵ is independently selected from the groupconsisting of C₁-C₈-alkyl, C₆-C₁₄-aryl, and heterocyclyl or N(R⁵)₂ as awhole is a N-containing heterocycle the process comprising at least thestep of reacting compounds of formula (II)P_(x)(R^(H))_((m+p))(R¹)_(n)  (II) wherein R^(H), R¹, x, and n and thesum of (m+n+p) is as defined above for the sum of (m+n+p) for compoundsof formula (I) with s being 0 where x=1 and the sum of (m+p) is aninteger of 1 or more that fits the equation given for the sum of (m+n+p)for compounds of formula (I) with s being 0 where x is 1 with compoundsof formula (III),R²COHal  (III) wherein R² is as defined above for compounds of formula(I) and Hal represents fluoro, chloro, bromo or iodo whereby thereaction is carried out in the presence of at least one Lewis acid. 8.The process according to claim 7, wherein in compounds of formulae (I)and (III) R² is C₆-C₁₄-aryl or C₄-C₁₃-heteroaryl.
 9. The processaccording to claim 7, wherein as compounds of formula (II) phosphine(PH3), tris(trimethylsilyl)phosphine (P(SiMe)3) ortris(trimethylsilyl)-heptaphosphine ((P7(SiMe)3) are employed.
 10. Theprocess according to claim 7, wherein as compounds of formula (I)benzoylphosphine, mesitoylphosphine, bismesitoylphosphine,dibenzoylphosphine dichloroaluminyl-bismesitoylphosphide,difluoroboryl-bismesitoylphosphide,dichloroaluminyl-bisbenzoylphosphide, difluoroboryl-bisbenzoylphosphide,chloroaluminyl-bis(bismesitoylphosphide),chloroaluminyl-bis(bisbenzoyl-phosphide),chloroboryl-bis(bismesitoylphosphide),chloroboryl-bis(bisbenzoyl-phosphide),aluminium-tris(bismesitoylphosphide),aluminium-tris(bisnaphthoylphosphide) and/oraluminium-tris(bisbenzoylphosphide) are prepared.
 11. The processaccording to claim 7, wherein the at least one Lewis acid is selectedfrom the group including methyl aluminoxane (MAO) and compoundsrepresented by formula (IV)MR^(L) _((r))X_((z-r))  (IV) wherein z is 2, 3, 4 or 5 r is 0 or aninteger of at maximum z M if z is 2 is an element selected from thegroup consisting of Sn, Zn, Fe and Mn if z is 3 is an element selectedfrom the group consisting of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy,Ho, Er, Tm, Yb, Lu, Fe, B, Al, Ga, In, As if z is 4 is an elementselected from the group consisting of V, Ti, Zr, Hf, Sn if z is 5 is anelement selected from the group consisting of V, P, As, Sb, Bi X isindependently selected from the group consisting of fluoride, chloride,bromide, iodide, azide, isocyanate, thiocyanate, isothiocyanate orcyanide R^(L) represents C₁-C₁₈-alkyl, C₁-C₁₈-halo alkyl, C₁-C₁₈-alkoxy,C₁-C₁₈-haloalkoxy, C₁-C₁₄-aryl, C₇-C₁₈ arylalkyl, C₆-C₁₄-aryloxy,C₇-C₁₈-arylalkoxy, —O(HC═O), —O(C═O)—(C₁-C₁₈-alkyl),—O(C═O)—(C₆-C₁₄-aryl) and —O(C═O)—(C₇-C₁₈-arylalkyl) or two R^(L)together represent C₄-C₁₈-alkandiyl, C₄-C₁₈-haloalkandiyl,C₄-C₁₈-alkanedioxy, C₄-C₁₈-haloalkanedioxy, C₆-C₁₄-aryldiyl,C₇-C₁₈-arylalkanediyl, C₆-C₁₄-aryldioxy, C₇-C₁₈-arylalkanedioxy,—O(C═O)—(C₁-C₁₈-alkyl)-(C═O)O—, —O(C═O)—(C₆-C₁₄-aryl)-(C═O)O— and—O(C═O)—(C₇-C₁₈-arylalkyl)-(C═O)O—, or oxo (═O).
 12. The processaccording to claim 11, wherein the Lewis Acid Fragments (LAF) arestructural units of formula (IVa)MR^(L) _((rr))X_((zz-rr))  (IVa) wherein M, X and R^(L) shall have thesame meaning as described for formula (IV) zz is (z-q) with q being aninteger of 1 up to z, wherein z shall have the same meaning as describedfor formula (IV) and rr is 0 or an integer of at maximum zz.
 13. Theprocess according to claim 7, wherein the Lewis Acids are aluminumtrichloride and/or boron trifluoride.
 14. A process for preparingcompounds of formula (Ib)HP(COR²)₂  (Ib) by reacting compounds of formula (Ia) according to claim1 with a proton source.
 15. A process according to claim 14 whereinproton sources include water, acids and alcohols or a mixture thereof.16. A method comprising reacting compounds of claim 1 as precursormaterials for substituted bisacylphosphine oxides.